Evaluation of Effect of Zirconia Surface Treatment with CO(2) and Nd:YAG Lasers on Shear Bond Strength between Zirconia Frameworks and Porcelain Veneers.

AIM: The purpose of this study was to evaluate the effect of zirconia surface treatment with CO(2) and Nd:YAG laser on shear bond strength (SBS) between the zirconia framework and porcelain veneering. MATERIALS AND METHODS: In this in vitro study, zirconia blocks were converted to 50 cubes and were divided randomly into 5 groups. After sintering (S), porcelain was applied in the control group. The surface treatment of the second to fifth groups included CO(2) laser + (S), (S + CO(2)), Nd:YAG laser + (S), and (S + Nd), respectively. The SBS test was done, and data were analyzed by SPSS16 software. One sample was randomly chosen from each group and the type of failure was examined under scanning electron microscope (SEM). To compare the pairs of means, the least significant difference test was used and the determined significance level was 5% (p < 0.05). RESULTS: The SBS of S + Nd group was significantly higher than the other ones, except for S + CO(2) group. The least amount of SBS belonged to CO(2) + S and the highest to S + Nd group. There were no significant differences between the other groups. CONCLUSION: The bond strength of veneering porcelain to zirconia can be altered by surface treatments. It can also be affected by the type and sequence of laser and sintering application. The effect of Nd:YAG laser on the surface of zirconia, in order to create roughness to increase SBS, is better than that of CO(2) laser. CLINICAL SIGNIFICANCE: Surface treatment of zirconia by certain types of lasers reduces the chipping of the ceramic veneer and increases the success rate of all-ceramic restorations.